Reverse pass in-line veneer production system



C. DODGE Filed March 27, 1967 \w kw mm INVEN'IOR. CONA/YT DODGE A T TOR/YE YS REVERSE PASS IN-LINE VENEER PRODUCTION SYSTEM June 3, 1969 United States Patent O 3,447,579 REVERSE PASS IN-LINE VENEER PRODUCTION SYSTEM Conant Dodge, Tacoma, Wash, assignor to Weyerhaeuser Company, Tacoma, Wash., a corporation of Washington Filed Mar. 27, 1967, Ser. No. 626,154 Int. Cl. B27h 1/00; B27c 9/100 US. Cl. 144-324 6 Claims ABSTRACT OF THE DISCLOSURE CROSS REFERENCES TO RELATED APPLICATIONS This application relates to an in-line veneer production system which was developed as a modification to that shown in the US. Patent No. 3,280,866 to Harold E. Erickson to permit application of the in-line system to plants of lesser capacity, resulting in more efiicient use of manpower and machinery.

A method for increasing the efliciency of the dryer disclosed in the instant application is disclosed in U.S. Patent application Ser. No. 630,567, filed Apr. 13, 1967, in the name of Albert S. Hammond, having a common assignee with the instant application. An apparatus useful in holding the veneer against the turn-around drum shown in the instant application is more particularly described in US. patent-application Ser. No. 629,783, filed Apr. 10, 1967, in the name of Eric B. Denton, having a common assignee with the instant application. 6

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the production of wood veneers and in particular to an improved process for in-line production of wood veneers utilizing a turn-around drying chamber.

Description of the prior art 7 The numerous advantages provided by an in-line veneer production system are fully disclosed in the US. Patent No. 3,280,866 to Harold E. Erickson. While the Erickson system provides an excellent method for producing a large quantity of dried wood veneer, the efliciencies of this system may be obtained only by those installations where a relatively large quantity of logs is available for peeling into veneer. The Erickson system requires a substantial length of building to house in one long line the veneer accumulating storage conveyors and the single pass dryer along with the cooling section and sorting table. .The waste wood resulting from the peeling and waste removal operations can be easily conveyed to one end of the building to be processed by one chipping facility, but the waste wood that is developed at the sorting table must be processed from the extreme end of the building, requiring another chipping facility. In addition, personnel supervising the machine operators in the Erickson system must transit the full length of the dryer to supervise the conduct of the sorting, waste clipper and dryer feeder crews.

Turn-around dryers as such are not new to the veneer drying field. One such dryer is disclosed in the US. Patent No. 1,511,400 to Daly, wherein the veneer passes over the top of the dryer and then is weaved back and forth two times through the dryer so that it exits from the same end of the dryer that it came into it. A multiple pass turnaround dryer is also shown in the Russian Patent No. 137,663, wherein the veneer feeds into the top of the dryer, makes several back and forth passes through the dryer, and then exits from the bottom of the dryer at the other end. Two other single line, double pass turnaround dryers are shown in schematic form in the article entitled, Continuous Veneer Drying, Nov. 1965 issue of Board Manufacture, a publication of Press Media Limited, Ivy Hatch Seven Oaks, Kent, England. One of the common features of all of the above referred to turnaround dryers is the fact that the point where the veneer is caused to change its direction is located within the housing of the dryer, and therefore it is impossible, without opening up the dryer, to reposition the veneer as it makes its pass through this critical portion of its path.

SUMMARY OF THE INVENTION Applicant has developed an in-line veneer production system which obtains the material handling and other operating efficiencies of the above referred to Erickson system suitable for smaller capacity production facilities. By positioning the peeling lathe, accumulating conveyors, waste removal clipper, cooling chamber, sizing clipper and sorting table at one end of the turn-around drying chamber, applicant has been able to obtain new efi'iciencies in personnel supervision and material handling. All but one member of the production crew is easily supervised by observing the operations between the lathe and drying chamber. All of the waste wood produced at the lathe, Waste removal clipper and sizing clipper can be easily gathered at a location at one end of the dryer to be processed in one chipping facility. The overall length of the building housing applicants system is reduced as compared with the single pass dryer line and sorting table length requirements of the Erickson system. With applicants novel dryer turn-around mechanism installed external to the dryer housing, it is possible to make adjustments to the veneers position as it changes direction without having to open up the dryer. Other related features of the invention will become more fully apparent as the following description is read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIGURE 1 is a side elevation view of the general arrangement of the in-line veneer production system of the instant invention; and

FIGURE 2 is an enlarged side elevation view of the turn-around portion of the veneer dryer.

3 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings with more detail, the improved in-line veneer production system 1 is shown in FIGURE 1. Following the path of the veneer from left to right, the system 1 includes a log peeling lathe 5, a series of veneer accumulating conveyors 20, a waste removal clipper 35, a drying chamber 50, a turn-around mechanism for the dryer 65, a cooling section 80, a sizing clipper 90, a sorting table 100 and a waste wood receiving bin 110.

The peeling lathe 5 may be of any conventional design wherein logs are turned by a suitable drive means against a sharpened knife to produce a ribbon of wood veneer 6. The veneer 6 is conveyed from the lathe 5 across a gate conveyor 7, shown in solid lines in its normal or first position for conveying the veneer ribbon 6 from the lathe 5 to the accumulating conveyors 20. The dash line representation shows the gate 7 in its lowered or second position for conveying scrap wood to the bin 110, where this rough-cut waste wood can be further conveyed by means of chipper conveyor 111 to a chipping facility to be made into usable wood chips.

The veneer ribbon 6, which passes over gate 7, is then conveyed by means of tipples 9, which can be elevated at one end, to transport the veneer ribbon 6 to any one of the series of veneer accumulating tray iconveyors 10, 11, 12, 14 or 16. With this arrangement, the lathe 5 may operate at its highest speed and the veneer 6 can be accumulated prior to its passage through the drying chamber 50.

Since some portions of the veneer ribbon 6 will be long and relatively free of any defects, it is possible to accumulate these ribbons on the upper two accumulating trays 10, 11 so that they may be fed into the dryer chamber 50 without further processing. However, there are many portions of peeled logs which are not completely sound, and these do not produce wide ribbons. These portions of veneer are nonetheless valuable and can be salvaged by proper Iclipping. Such veneer sheets, having some defective portions, are therefore directed by the lathe operators positioning of the tipples 9 to one end of the lower sets of accumulator conveyors 12, 14 or 16. These pieces of veneer accumulated on trays 12, 14 and 16 are passed through the waste removal clipper 35 where the obviously unusable sections are clipped away and the useful sections are conveyed on to the second set of accumulating conveyors 13, 15 and 17 prior to being fed into the drying lchamber 50.

The waste removal clipper 35 includes a pivoting infeed conveyor 36, which pivots about one end so that the other end may be positioned in registry with any one of the lower accumulator conveyors 12, 14 or 16. The waste removal clipper may be of conventional design and includes a clipping knife (not shown) which severs the veneer to separate the obviously unusable portions which are not worth drying from those portions which are of a higher quality and are useful if they are properly dried. A gate conveyor 37 is positioned on the exit side or the waste removal clipper 35 to accomplish substantially the same function that is provided by the gate conveyor 7 adjacent the peeling lathe 5. In its first or normal position, shown in solid lines, the gate 37 conveys the sound veneer to the pivoting conveyor 38, so that it may pass to the second set of lower accumulator conveyors 13, 15 or 17. In its lowered or second position, shown in dash lines, the gate 37 conveys the unusable portions of the veneer down into a Waste chute 39 for further transit to the waste bin 110 along a waste removal conveyor 40.

To provide a means of transporting the useful veneer from the veneer accumulating conveyors 20 to the drying chamber 50, a dryer feeding tipple 45 is pivoted about its one end adjacent the drying chamber 50 so that its other end may be positioned in registry with the veneer accumulating conveyors 10, 1'1, 13, 15 and 17.

All of the conveyor gates, tipples and other conveyor lines are equipped with conventional drive means [for moving the conveying belts. As shown, one portion of the veneer 6 is being conveyed trom the peeling lathe 5 along the gate 7, tipples 9, to the accumulating conveyor 12. This operation is done at the optimum speed for the peeling means 5. At the same time, another portion of veneer 19 is being conveyed from the upper accumulating veneer conveyor 10 down along the dryer tipple 45 to the drying chamber 50 'at a speed which will provide the best drying results as the [veneer 19 passes through the drying chamber 50. While this embodiment specifies the use of in-line accumulating and waste removal clipping of the veneer prior to drying, it should be understood that well known conventional processes, including clipping the veneer to allow for shrinkage and reeling the veneer prior to drying, could be used with the turn-around dryer to obtain applic-ants supervision and waste wood handling efficiencies.

The dryer chamber 50 may include a suitable source of heating medium (not shown) and any conventional dryer housing which will provide a longitudinal enclosure suitable for retaining the heating medium and circulating it so that the moisture content of the veneer is reduced as it passes through the dryer chamber 50. To convey the veneer ribbon through the dryer chamber 50, there is provided a number of carrying and holddown cables, belts or other suitable conveying means. As shown, the upper hold-down cable 52 spans from one end of the dryer chamber 50 to the other and is supported at one end about pulley53 and at the other end about pulley 54. Any suitable drive means may be used to move the upper hold-down cable 52 in a continuous path through the dryer chamber 50, so that the portion of the hold-down cable 52, which is in contact with the upper surface of the veneer, travels in a direction from left to right. The upper carrying cable 56 also serves as the lower hold-down cable. It is supported at one end by large pulley 57 and at the other end by the turn-around drum 58. The lower carrying cable 60 is supported at one end by pulley 61 and at the other end by pulley 62. \As shown, the upper cable 52 operates in a counterclockwise direction; the upper carrying cable 56, which is also the lower hold-down cable, operates in the clockwise direction; and the lower carrying cable 60 operates in the counterclockwise direction. While the cables 52, 56 and 60 have been referred to as singular cables, in practice two or more cables are spaced along the width of the drying chamber 50 to provide adequate support for the veneer. It is also possible to use wide screens in a band rform, belts and even rollers in place of the cables to convey the veneer through the drying chamber 50.

As the veneer passes through the dryer chamber 50, it is supported by the upper carrying cable 56 and is held down from above by the upper hold-down lcable 52, until it transits the full length of the dryer chamber 50, at which time it emerges into the open, to the location of the turn-around mechanism 65. Then it passes between the cable 56 and the hold-down belts 66, which hold the veneer against the cable 56 as it turns around the drum 58. The belts 66 are generally not driven belts but idle about their pulleys 67, 68 and their tensioning pulley 69. The belts 66 rotate through the frictional contact with the veneer as it passes between the belts 66 and the cable 56 around the drum 58. 1f the veneer becomes dislocated or jammed, it is possible to adjust its position at the turn-around mechanism 65, since this is not enclosed by the dryer housing 50* and permits access to the veneer as it passes out of the dryer chamber. To complete its drying process, the veneer returns through the drying chamber 50 along the lower path de- 5 fined between the lower carrying cable 60 and the hold: down cable 56.

Since the veneer becomes heated in the drying chamber 50, it is .desirable that it become cooled prior to its being handled during the sorting operation. To accomplish this cooling, the veneer, as it exits from the lower path through the drying chamber 50, is conveyed directly into a cooling chamber 80. The veneer is conveyed through the cooling chamber 80 by an upper hold-down conveying band or cable 81 which is supported and driven through pulleys -82, 83, and a lower carrying cable or band 85 which is supported and driven through'pulleys 86, 87. The cooling chamber '80 is generally equipped with large fans (not shown) which take the air from the atmosphere and pass it around the veneer so that it will become cool enough to handle by the time it is discharged from the cooling chamber 80.

As the veneer exits from the cooling chamber 80, it may pass a moisture meter 88, which will indicate to the clipper operator whether the veneer has reached the proper range of moisture content. The sizing clipper 90 is then used to clip the veneer ribbon to appropriate sizes for further use in production of plywood. This clipping operation may be made in accordance with grade and moisture content. From the veneer sizing clipper 90 the veneer passes on to a long sorting table conveyor 100, where it is sorted by a sorting crew in accordance with size and grade. Pieces of dry scrap which are damaged, or are of such a size that they would not be useful in the production of plywood, are allowed to transit the full length of the sorting table 100 and fall into the waste bin 110 to be further processed into wood chips.

In operation, it is seen that the veneer is peeled from logs at the peeling lathe 5 and conveyed past gate 7, tipples 9, to the accumulating veneer storage conveyors 20, and then is transported along the dryer tipple 45 to the upper line of the drying chamber 50, as formed by the cables or bands 52, 56, so that the veneer passes from one end of the dryer to the other. As it exits from the far end of the dryer 50, the veneer is passed around the turn-around drum 58 and starts its return path along the lower carrying conveyor 60, held down by the holddown cable 56. As the veneer exits from the dryer chamber, it is immediately conveyed into the cooling chamber 80, where it is cooled so that it can be handled. As the veneer exits from the cooling chamber, its moisture content is sensed, and it is clipped by the sizing clipper 90 to appropriate sizes in accordance with grade and moisture content. The veneer is then sorted along the sorting table 100, and any unusuable portions of the veneer, herein referred to as dry scrap, are permit-ted to pass along the full length of the sorting table 100 and fall into the waste bin 110. Sections of veneer which contain unusuable defects are passed from the tipple 9 onto the lower sets of accumulating conveyors 12, 14 or 16, so that the unusable portions of the veneer may be cut away by the waste removal clipper 35 and conveyed down into the waste bin 39, back along the conveyor 40 into the waste bin 110.

It is therefore seen that all of the waste wood which results from the veneer production process-that is, the waste formed by the peeling lathe 5 while the rough portions of the log are being peeled away, the unusable sections which are removed by the waste removal clipper 35, and the dry scrap which is allowed by the sorting crew to pass along the full length of the sorting table 100-is gathered together at one end of the production line in the waste bin 110 where it can be transited by a single chip conveyor 111 to be further processed by a single chipping facility (not shown) into useful wood chips. It is also seen that by providing a reverse pass dryer, it is possible to shorten the overall length of the in-line veneer production system so that the major por tion of supervision of the crew can be directed at one end of the dryer. It would be customary to station one man at the turnaround section of the dryer to reposition and straighten any dislodged veneer as it passes through the turnaround section 65.

It is therefore seen that I have disclosed a generally improved in-line veneer production system suitable for smaller capacity plants which permits the realization of the material handling and manpower efiiciencies of the Erickson in-line system without its requirement for large long installations, spread out supervision and multiple chip production facilities.

What is claimed is:

1. In an apparatus for the production of dried wood veneers:

a drying chamber having a first and second end;

first means for transporting the veneer through said drying chamber from said first end to said second end;

second means for transporting said veneer through said drying chamber from said second end to said first end;

turn-around means positioned adjacent said second end of said drying chamber and external thereto for conveying said veneer from said first means to said second means; and

said drying chamber including means for heating said veneer as it is passed through said drying chamber.

2. The apparatus of claim 1 including:

a cooling chamber having an entrance and exit end;

cooling transport means for conveying veneer from said entrance end to said exit end;

said cooling chamber including means for exposing said veneer to a cooling medium as it is transported through said cooling chamber; and

said cooling transport means positioned to receive said veneer from said second means as said veneer reaches said first end of said drying chamber.

3. The apparatus of claim 1 including:

peeling means for peeling veneer and scrap wood from logs;

conveyor gate means positioned adjacent said peeling means to convey the peeled material away from said peeling means toward said drying chamber;

said conveyor gate means having a first end adjacent said peeling means and a second end closer to said drying chamber and positioned through drive means between a first and second position; rough-cut scrap wood receiving means adjacent said second end of said conveyor gate means when it is in said second position for directing said scrap wood from said conveyor gate means to a waste bin;

veneer accumulating means having a receiving end and a discharge end;

said receiving end in register with said second end of said conveyor gate means when it is in said first position for directing said peeled material from said conveyor gate means through said accumulator means to said discharge end;

said discharge end including feeding means in register with said first means at said first end of said drying chamber to convey said peeled material into said drying chamber; and

conveying means including a sorting table conveyor for transporting dry scrap veneer from said second means at said first end of said drying chamber to said waste bin.

4. The apparatus of claim 3 including:

waste removal clipper means positioned within said veneer accumulator means between said receiving and discharging end for clipping unusable sections away from said veneer as it is transported from said peeling means to said drying chamber; and

waste conveyor means for receiving said unusable sections of said veneer from said waste removal clipper means and transporting it to said waste bin.

5. In an in-line process for producing veneer wherein logs are peeled at a peeling station to produce veneer 7 and scrap wood, the scrap wood is collected in a scrap bin, the veneer is conveyed through a drying chamber to reduce its moisture content; the improvement compris- (a) conveying said veneer through the drying chamber first in a direction away from its first end closest to said peeling station and then in a direction toward said first end; and

(b) conveying the dried scrap veneer out of said drying chamber to said scrap bin to combine it with said scrap wood produced from said peeling.

6. The process of claim 5 wherein the unusable sections of said veneer are separated from said veneer before it is conveyed through said drying chamber; the improvement comprising: v conveying said unusable sections of said veneer to said scrap bin to combine it with said scrap wood and said 7 dried scrap veneer. i

References Cited UNITED STATES PATENTS 3,280,866 10/ 1966 Erickson 144-324 GERALD A." DOST, Primary Examiner.

7 s. 01. X.R. 144 3; 19s-2o 

